feat(tasks): add skill-templated task graph execution

app-instance/backend/beaver/tools/runtime/executor.py

@@ -37,6 +37,14 @@ class ToolExecutor:
     ) -> ToolResult:
         """按工具名执行一次调用。"""
 
+        allowed = context.metadata.get("allowed_tool_names") if context is not None else None
+        if isinstance(allowed, list) and tool_name not in allowed:
+            return ToolResult(
+                success=False,
+                content=f"Tool {tool_name} is not allowed for this node.",
+                tool_name=tool_name,
+                error="tool_not_allowed",
+            )
         tool = self.registry.get(tool_name)
         if tool is None:
             return ToolResult(